Two- or three-dimensional image data, which may be used for visualizing an imaged examination subject and in addition for further applications, is frequently generated with the aid of modern imaging methods.
In three-dimensional medical imaging, it is often necessary to represent three-dimensional image data or, as the case may be, volumetric geometric structures present in the image data in a suitable way with the aid of a geometric model in order to enable measurements to be taken or to conduct a diagnostic analysis at a higher level. This procedure is referred to in the following also as “volume object modeling”.
Examples of such more complex approaches for diagnostic purposes are the simulation of the blood flow through the coronary vessels of the heart by modeling the fluid dynamics and the examination of plaque deposits in cases of arteriosclerosis. In order to be able to carry out these investigations it is necessary to translate the measurement signals or measurement data into a meaningful geometric semantic system relating to the imaged structures. Toward that end, methods for segmenting acquired medical images have been developed with the aid of which an image volume is divided up into known objects either in an automated manner or interactively. Unfortunately, fully automatic methods are often extremely prone to errors and for that reason must be supplemented by suitable interactive methods in order to achieve an additional “refinement” of the automatically determined segments and geometric model structures associated therewith.
In an example application, the entire vascular structure of the coronary tree perfused by the blood is modeled interactively on the basis of image data obtained through cardiac computed-tomography angiography (CCTA). Existing interactive methods from the prior art are not very user-friendly and typically are limited to linear planar two-dimensional representations of the actual 3D data, such as, for example, to representations which have been obtained by way of a multiplanar reformation perpendicularly to the centerlines of the vessels. Within the framework of these interactive modeling techniques, surface markings, such as open or closed aggregations of surface points, for example, are edited or marked in order to be used for a subsequent segmentation. The multiplanar reformation comprises sections of the three-dimensional data in which the editing is carried out. In most cases, however, the course of the individual vessels is not consistent with these sections, with the result that an editing operation based on these sections is incomplete and may easily lead to incorrect results.